What is the value of a 1904 Morgan dollar?
Assuming the coin is circulated and has no mintmark, the 1904 Morgan dollar is a little better date coin. For an accurate assessment of value the coin needs to be seen and graded. In general retail values for low grade coins are $36.00-$39.00, better grade are $40.00-$43.00 and coins showing almost no wear run from $45.00-$49.00. Values are a market average and only for coins in collectible condition, coins that are bent, corroded, scratched, used as jewelery or have been cleaned have far less value if any to a collector or dealer.
A 1922 dollar with the word "Peace" on the back would be a Peace dollar rather than a Morgan dollar. "Morgan" refers to George T. Morgan, the artist who designed the silver dollars minted from 1878 to 1904 and in 1921. There's more information at the question "What is the value of a 1922 US silver dollar?"